Upgrade @polkadot/api and @polkadot/util package version to latest (#2821)

Otherwise I'm getting this error:
https://github.com/polkadot-js/api/pull/4952/files#diff-4cab1e3a83a624e52dc0c30047addb28184fdceac6acb930787af9c3aac50706L668
when running `./cumulus/scripts/bridges_rococo_westend.sh
init-bridge-hub-rococo-local` - guess it is related to recent Snowbridge
merge?

cumulus/scripts/generate_hex_encoded_call/package.json

@@ -5,7 +5,7 @@
   "main": "index.js",
   "license": "MIT",
   "dependencies": {
-    "@polkadot/api": "^6.5.2",
-    "@polkadot/util": "^7.6.1"
+    "@polkadot/api": "^10.11",
+    "@polkadot/util": "^12.6"
   }
 }